<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <div>
        <!-- JS变量 -->
        <!-- 存储信息的容器 -->
        <div>
            <script>
                var x = 5;
                var y = 6;
                var z = x + y;
                document.write(x + "<br>");
                document.write(y + "<br>");
                document.write(z + "<br>");
            </script>
        </div>
        <hr />

        <div>
            <script>
                var pi = 3.14;
                var name = "Bill Gates";
                var answer = 'Yes I am!';
                document.write(pi + "<br>");
                document.write(name + "<br>");
                document.write(answer + "<br>");
            </script>
        </div>
        <hr />

        <div>
            <p>点击这里来创建变量，并显示结果。</p>
            <button onclick="myFunction()">点击这里</button>
            <p id="demo"></p>
            <script>
                function myFunction() {
                    var carname = "Volvo";
                    document.getElementById("demo").innerHTML = carname;
                }
            </script>
        </div>

        <hr />
        <div>
            <p>假设 y=5，计算 x=y+2，并显示结果。</p>
            <button onclick="myFunaaaaction()">点击这里</button>
            <p id="dadawemo"></p>
            <script>
                function myFunaaaaction() {
                    var y = 5;
                    var x = y + 2;
                    var demoP = document.getElementById("dadawemo")
                    demoP.innerHTML = "x=" + x;
                }
            </script>
        </div>
    </div>
</body>

</html>